This is the first RCT to examine prebiotic-induced changes in overweight children’s gut bacteria. The findings may have big implications for future dietary treatment of obesity as prebiotics are cheap, easy to consume and non-invasive.

"Powdered fiber, mixed in a water bottle, taken once a day is all we asked the children to change, and we got, what we consider, some pretty exciting results -- it has been fantastic," ​commented Reimer.

Trunk fat, particularly around the abdomen, is widely recognised to increase diabetes risk and poor metabolic outcomes. High serum triglycerides may be involved in insulin resistance, while IL6 is an important biomarker of low-grade inflammation frequently present in obesity.

Microbiome modification​

The researchers were keen to emphasise the significant role played by the prebiotic. “Importantly, we have shown that OI induced specific gut bacterial shifts compared to placebo,” ​they stressed.

Consuming the prebiotic selectively alters the gut microbiota in overweight children demonstrating “Significant increases in species of the genus Bifidobacterium and decreases in Bacteroides vulgatus within the group who consumed OI​,” noted the research team.

Previous research has identified an association between Bacteroides vulgatus​ and obesity in women.

High levels of Clostridium clostridioforme​ have previously been seen in diabetic patients.

“Clostridium clostridioforme in the present study, decreased in prebiotic versus placebo, and it was significantly positively correlated with changes in different biological and compositional outcomes,”​ the researchers said.

Although the team acknowledge that incomplete understanding still exists of exactly what makes up a healthy microbiota, the identification of a possible causal link between gut bacteria composition and reducing obesity is a big step forward.

The findings provide a wider foundation for larger clinical trials among overweight children. Intervention at a young age, such as the 7-12 year-olds in this study, may also reduce the likelihood of obesity-related diseases in adulthood and premature death resulting from long-term overweight.